Local topical anesthetics for the eye are generally used with caution since the decrease in blinking and subsequent dehydration may cause damage to the corneal epithelium. For non-surgical situations, the eye care professional would want anesthesia in the eye which would last only as long as the desired procedure. Such a procedure may be quite short, and there is thus a need for a fast acting and yet transient topical anesthetic for the eye. Such an anesthetic would minimize the keratitis caused by the lack of or decreased rate of blinking.
Injectable anesthetics are used in the eye by retro-bulbar injection to prevent the eye muscles of the patient from moving during sugery. For example, during cataract surgery, the lens of the eye is replaced, and the ophthalmologist will normally anesthetize the retro-bulbar muscles and nerves to keep the eye still during the delicate procedure. Many such surgeons use a combination of drugs to achieve the proper anesthetic profile. For example, lidocaine may have a quick inset while bupivacaine provides a longer action. However, such mixing is an obvious disadvantage.